Six men, five days a week, occupy their same seats in the same first class compartment on a train to and from London. One morning one of the men doesn’t show up. His place is taken by a man dressed all in black wearing dark sunglasses. When it is pointed out that the seat is taken, the man states “He won’t be coming.”

This is the beginning of a mystery with many twists and turns and connections between the characters.

The missing man is found dead in his car. Suicide is the declared cause, due to a bottle of pills found in the car. But was it?

There is the matter of a will that has been rewritten. Where is it and what were the changes? Who benefits and who was written out?

There is the missing briefcase. What was in it and what happened to it?

And there is more. Carolus Deene’s investigations explore and track down the thread and untangles them to develop a detailed solution to the number of mysteries involved.

Not a simple mystery. ( )